From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753389AbbLJQ1h (ORCPT ); Thu, 10 Dec 2015 11:27:37 -0500 Received: from mail.skyhub.de ([78.46.96.112]:48414 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751084AbbLJQ1g (ORCPT ); Thu, 10 Dec 2015 11:27:36 -0500 Date: Thu, 10 Dec 2015 17:27:33 +0100 From: Borislav Petkov To: linux-ext4@vger.kernel.org Cc: Jan Kara , "Theodore Ts'o" , Paolo Bonzini , lkml Subject: Re: ext4/jbd splat in 4.4-rc4+ Message-ID: <20151210162733.GA6587@pd.tnic> References: <20151210140404.GA3049@nazgul.tnic> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20151210140404.GA3049@nazgul.tnic> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Dec 10, 2015 at 03:04:04PM +0100, Borislav Petkov wrote: > Hi guys, > > I'm getting this nasty splat in ext4 land while booting kernels in > qemu/kvm. Last time it happened while injecting NMIs in the guest using > the qemu monitor, this time too. Any ideas? > > Sadly, rIP is gone so I can't really pinpoint the problem but someone > might have an idea. > > Last time it happened, the box froze solid, this time it was barely > alive so that I was able to suck dmesg out before it crashes completely. > > Any suggestions appreciated. Hmm, got a second one, again during injecting NMIs in the guest, the *host* exploded like this. And this time not in ext4 which would mean, some corruption is happening. Paolo, any ideas? What happens when I do "nmi" in qemu's monitor, why does it corrupt the host? Lemme test plain rc4 in the guest... [ 3405.741284] kvm: zapping shadow pages for mmio generation wraparound [ 3451.874613] kvm: zapping shadow pages for mmio generation wraparound [ 4493.572305] kvm: zapping shadow pages for mmio generation wraparound [ 4519.739695] BUG: unable to handle kernel NULL pointer dereference at (null) [ 4519.751390] IP: [< (null)>] (null) [ 4519.760275] PGD 0 [ 4519.766054] Oops: 0010 [#1] PREEMPT SMP [ 4519.773785] Modules linked in: tun sha256_ssse3 sha256_generic drbg binfmt_misc ipv6 vfat fat fuse dm_crypt dm_mod kvm_amd kvm irqbypass crc32_pclmul aesni_intel aes_x86_64 lrw gf128mul glue_helper ablk_helper cryptd fam15h_power k10temp amd64_edac_mod edac_mce_amd amdkfd amd_iommu_v2 radeon acpi_cpufreq [ 4519.809462] CPU: 4 PID: 32028 Comm: qemu-system-x86 Not tainted 4.4.0-rc4+ #1 [ 4519.820667] Hardware name: To be filled by O.E.M. To be filled by O.E.M./M5A97 EVO R2.0, BIOS 1503 01/16/2013 [ 4519.834710] task: ffff880423715e00 ti: ffff88040f3a8000 task.ti: ffff88040f3a8000 [ 4519.846340] RIP: 0010:[<0000000000000000>] [< (null)>] (null) [ 4519.857998] RSP: 0018:ffff88040f3abe38 EFLAGS: 00010286 [ 4519.867492] RAX: ffff880423715e00 RBX: 0000000000000286 RCX: 0000000000000001 [ 4519.867494] RDX: ffff8804237164e0 RSI: 0000000000000000 RDI: ffff880423715e01 [ 4519.867496] RBP: ffff88040f3abe90 R08: 0000000000000000 R09: 0000000000000000 [ 4519.867497] R10: 0000000000000000 R11: 0000000000000007 R12: 0000000000000000 [ 4519.867498] R13: 0000000000000002 R14: 0000000000000000 R15: 0000000000000000 [ 4519.867501] FS: 00007ff557300700(0000) GS:ffff88042ce00000(0000) knlGS:0000000000000000 [ 4519.867503] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b [ 4519.867505] CR2: 0000000000000000 CR3: 000000040f018000 CR4: 00000000000406e0 [ 4519.867506] Stack: [ 4519.867511] ffffffff811ac675 ffff880400000000 0000000000000000 0000000000000286 [ 4519.867515] 000000000f3abe78 ffffffff81a3c1e0 ffff8804288616c0 0000000000000009 [ 4519.867519] 0000000000000000 0000000000004000 00007ff5572ffab0 ffff88040f3abed8 [ 4519.867520] Call Trace: [ 4519.867529] [] ? __fget+0x5/0x210 [ 4519.867535] [] __fget+0x54/0x210 [ 4519.867540] [] ? __fget+0x5/0x210 [ 4519.867545] [] ? trace_hardirqs_on_caller+0xf2/0x210 [ 4519.867551] [] __fget_light+0x29/0x90 [ 4519.867562] [] __fdget+0x13/0x20 [ 4519.867565] [] SyS_ioctl+0x2f/0x90 [ 4519.867571] [] entry_SYSCALL_64_fastpath+0x16/0x6f [ 4519.867579] Code: Bad RIP value. [ 4519.867581] RIP [< (null)>] (null) [ 4519.867583] RSP [ 4519.867584] CR2: 0000000000000000 [ 4519.867655] ---[ end trace faf028eac08ef3a3 ]--- -- Regards/Gruss, Boris. ECO tip #101: Trim your mails when you reply.